Considerin d arrival of mesut ozil,sami khedira nd di'maria.whats d midfield selection gonna luk lyk?kaka,v.d.vaart,drenthe,diarra nd d aforementioned? If am d coach i'll b needin a anoda brain,tru talk.eeezz

There's also Esteban Granero, Sergio Canales, Xabi Alonso and Pedro Leon.
Kaka is out for 2-3 months and will also require additional time to become match fit.
There's also the need for depth. The players he chooses will depend on the formation he adopts. Canales is still a youngster so he will be used sporadically. The two Diarras' will likely move before the window closes. The only person who is assured of a place is Xabi Alonso. Mesut Ozil could deputise for Kaka till he returns. Angel Di Maria will likely play upfront on the left, CR on the right and Higuain/Benzema as the main striker.
Pedro Leon will be CR's main replacement while Khedira will deputise for Alonso

just remembered there's still Gago, van der Vaart, Drenthe. . .
I think Mourinho will adopt a similar tactics to the one he used at Inter-4-3-3
In the middle will probably be Alonso, Kaka, Granero. Too many options. Like you rightly said, Mourinho has some serious work to do. Besides, you can only register 25 players with a maximum of 4 non EU players.